upper 60s. more heat on the way. that's coming up at 6:00 passenger pollen report off the charts. >> time to take that allergy medicine. bye-bye. where does it end? riot police in the streets with part of ukraine now firmly in vladimir putin's control. president obama responds with sanctions. jolted awake. a big scare in southern california. the strongest earthquake to hit los angeles in years, renewing fears about the big one. "nightly news" begins now.

good evening. i'm lester holt sitting in for brian who will be back tomorrow. it is without a doubt the most baffling aviation mystery of our time, and it seems like everyone by now has a theory, a guess or opinion about what happened to malaysia airlines flight 370. after ten days the best investigators have been able to determine that the disappearance of the jet was a deliberate act and that it flew off somewhere in the northern or southern hemisphere. but the question of who is behind it has tonight cast suspicion on the pilots. even as officials again today revised the time line of this mystery. once again tonight tom costello leads off our expanded coverage. any signs of this search scaling back? >> reporter: a little bit. the pentagon telling us it is preparing to reduce the u.s. part of the search. the "uss kidd" will soon end search operations leaving only

p-8 and p-3 aircraft to search massive areas of water. and with no other country finding any sign this plane was ever on radar, the search zone is shifting to the south. just 500 feet above the indian ocean, a u.s. anti-submarine hunter today searching for any sign of flight 370. also today, more contradictions from malaysian authorities. after first saying the plane's last automated data or acars transmission was turned off before the last cockpit radio call, suggesting pilot involvement, today authorities backtracked. >> we don't know when the acars system was switched off. all we know is the last transmission. and we did not receive a next transmission. >> reporter: here's the latest time line. at 12:41 a.m. saturday, march 8th, flight 370 left kuala lumpur bound for beijing. at 1:07 a.m., it transmitted its last automated data burst, called acars.

the next acars transmission was scheduled for 30 minutes later. it never came. at 1:19 a.m. the co-pilot radioed "all right, good night" as malaysian air traffic controllers handed the plane over to vietnamese controllers. just two minutes after the very standard conversation, 1:21 a.m., someone in the cockpit turned off the transponders that send speed, location, altitude and heading information. soon after that the plane turned around. at 2:15 a.m., the last radar contact in the strait of mallacca headed north. over the next six hours the plane transmitted one ping per hour to an orbiting satellite until 8:11 a.m. when the last ping was received. that puts the plane somewhere along these two arcs as far north as kazakhstan, as far south as the deep indian ocean. australia is now taking over that search zone. >> we will do our duty to the families of the 230 people on that aircraft who are still absolutely devastated. >> reporter: experts say turning off acars and the transponders, then flying the 777 for hours, requires expertise which is why

there's intense focus on the cockpit crew. >> what is a potential motive, and what can be learned from looking deeply into the background of the pilot, the co-pilot and anybody else on that plane that had the skill to fly it. >> reporter: meanwhile, for the family of american philip wood, the wait is agony. >> i don't believe that the plane has been crashed. i haven't ever believed the plane has been crashed. it just doesn't make sense to me. and i don't feel like that's the right answer. >> reporter: investigators continue to look at the backgrounds of everyone on board, including an off-duty flight engineer. but his father tells nbc news he was not a pilot, he was only a mechanic. lester? >> all right, tom, thanks. while investigators say they're not ruling anyone out, they are taking a closer look at the captain and co-pilot of the plane. we'll get more on that tonight from nbc's keir simmons in kuala lumpur. >> reporter: video on youtube, unverified, appearing to show

the pilot and co-pilot passing through security. the pilot, zaharie shah, was known to love flying. he posted pictures on facebook with toy planes and helicopters. he had a flight simulator at home. that flight simulator is now in the hands of the police. they searched the pilot's home this weekend. it also emerged that the pilot had been active in malaysia's political opposition, but friends say that would not have motivated him to hijack his own plane. can you imagine him ever commandeering his own plane, putting his own passengers at risk? >> i cannot for one minute imagine him making that sort of decision. >> it just wouldn't make any sense that he would have anything to do with any sort of deliberate action on his part. >> reporter: officials say captain zaharie and his co-pilot fariq hamid had not requested to fly together. and they are investigating everyone aboard flight 370. but the co-pilot's house was

also searched. detectives were seen leaving with two of his relatives. the co-pilot could not have been involved, says the leader of his local mosque. >> because for me he's very good people. very humble, very innocent, respectable. >> reporter: it was the co-pilot, officials say, who was the last to speak to the control tower before the plane and everyone on board disappeared. keir simmons, nbc news, malaysia. >> again, tonight we turn to aviation expert, a former senior air safety director with the national transportation safety board and a veteran pilot. greg, always nice to have you here. >> thank you. >> there's no search area. there's an arc over a lot of land mass on this planet. you've got investigators right now who are used to combing through wreckage. nothing to comb through. this is a difficult question because people are waiting for loved ones right now, but are there going to have to be some hard decisions made in this -- in the coming days and weeks? >> absolutely, lester. there comes a point where you

have to really examine the return on investment. there are so many assets out there, so many countries that are participating, this stage of 11 days into this event if you will. because we're not really sure what kind of investigation to call it. accident or intentional act. i think the malaysians have said intentional act. so you have all these technical investigators sitting there waiting to do something. but they can't. there's going to come a point with this search area, it's so massive, that somebody's going to make a hard decision that they've done what they could with what they've had, and now we're going to have to find a point of calling it off and moving on. >> which is why hopefully detective work will come up with something in the meantime. >> absolutely. that's going to be the key to this because it is an intentional act, according to the malaysians. >> all right, so painful. thank you very much, appreciate it. much more on our website, including what experts say about the remote possibility this plane could have actually landed somewhere. that's at nbcnews.com. general motors today announced a new round of recalls as the nation's largest

automaker deals with investigations on multiple fronts. tonight gm's new ceo is in full damage control mode. nbc's gabe gutierrez is in detroit. >> reporter: more than 1.5 million suvs, vans and cadillacs are part of gm's second wide-ranging recall this year. >> this announcement underscores the focus we're putting on safety and peace of mind of our customers. >> reporter: today, gm's ceo, on the job just two months, made her first video statement. since the carmaker announced its first recall, 1.6 million other cars, last month. for an ignition problem linked to at least 12 deaths. >> as a member of the gm family and as a mom with a family of my own, this really hits home for me. we have apologized, but that is just one step in the journey to resolve this. >> reporter: this new round of recalls is not related to the ignition switch. the models include buick enclaves, gmc acadias, chevy

traverses and saturn outlooks, all being recalled for defective side airbags. >> this is a departure for general motors compared to the company we saw 10 or 15 years ago. mary barra has made it clear she wants to be as transparent as possible. >> reporter: also on the recall list, newer cadillac xtss for concerns that a brake booster pump could lead to an engine fire. chevy expresses and gmc savannahs, because gm says they don't meet head impact requirements. for some, convalescence in one of america's top brands is shaken. >> why spend the money if i'm not going to get the quality back? >> reporter: some analysts say the company will weather the storm. >> i think if you look at other companies out there that have had serious recalls over the past few decades, they've come back. >> reporter: but first, gm will have to face a separate criminal investigation and congressional hearings next month. there are no reported deaths or injuries related to this latest round of recalls. meanwhile, gm says it is expecting to take a $300 million

hit in the first quarter because of all this. lester? >> gabe gutierrez in detroit, thank you. now to the crisis in ukraine. tonight russian flags are flying in the crimean peninsula following a controversial vote over the weekend. despite a wave of sanctions from the white house and european union today, many are wondering just how far russia might go. we'll hear from richard engel in crimea in just a moment. first we're joined by our chief foreign affairs correspondent andrea mitchell in our washington newsroom. andrea, good evening. >> good evening, lester. vladimir putin was defiant tonight. signing the decree recognizing crimea's independence, ignoring economic sanctions today from the u.s. and europe. the russian president still strutting in the afterglow of the sochi games today awarding medals to the russian paralympians, seemingly unfazed by u.s. sanctions. as crimeans celebrated, u.s. officials tacitly acknowledged crimea is lost. so is a ukrainian natural gas

plant nearby, taken over by russia in a helicopter assault this weekend. the white house's new red line, any russian move into the rest of eastern ukraine. like donetsk, where pro-russian demonstrators were out in force. >> further provocations will achieve nothing except to further isolate russia. and diminish its place in the world. >> reporter: today the president froze american bank accounts and commerce with 11 top russian officials, crimean separatists, and ukrainian sympathizers. including former president yanukovych. if russia moves into eastern ukraine the president approved tougher measures against russia's arms industry, its oligarchs and putin's inner circle. >> we have tools available to us to really ratchet up the economic and financial cost on russia if we choose to do so. >> reporter: but on russia state tv, defiance, against a mushroom cloud the anchor said "russia is the only country in the world that is really able to turn the

usa into radioactive ashes." >> he works for the kremlin, there's no doubt about it. and i think it's important that the world now sees what has been on russian television for years. >> reporter: and critics say putin won't respond to economic pressure, no matter how close it hits to home. andrea mitchell, nbc news, washington. this is richard engel in crimea where today they welcomed their new patron, russia. ♪ >> reporter: those old enough to remember the soviet union celebrated the reunion with moscow. but the party here was decidedly one-sided. riot police out in force to make sure anyone opposed to moscow remained silent. there's no doubt the majority of people here are happy to join with putin's russia. but for the minority that doesn't want to, life just got a lot harder and maybe dangerous. hello. >> hello. >> nice to meet you. >> reporter: at a theater popular with activists, the director galina told us pro-russian thugs threw stun grenades into the crowded theater three times.

"they were attacking intellectuals, it's madness. she told us. many of my friends want to leave." 25-year-old diliara is packing tonight. three small suitcases. that's all she can carry with her. you're just going to close the door, lock it behind you, and go? >> yes. >> reporter: she's worried crimea under russia is becoming a police state. >> i'm not used to live like this. >> reporter: she fears crimea has voted away its freedom. richard engel, nbc news, crimea. still ahead tonight, fearing the big one. a scare in southern california. news anchors duck for cover during the strongest earthquake to hit l.a. in years. later, the shocking death of one of the top fashion designers in america, mick jagger's long-time companion found dead.

the nation's capital and other parts of the mid-atlantic

are cleaning up from another dose of winter. in washington more than half a foot of snow has fallen over the past 24 hours. it's one of the biggest late-season storms in that city's history. government workers as well as schoolkids got the day off. back now with that big scare before dawn this morning in southern california. a magnitude 4.4 earthquake shook millions of people awake in los angeles. the strongest quake to hit l.a. in years, renewing fears about when the big one will hit. nbc's miguel almaguer has our report. >> reporter: at 6:25 a.m., the violent jolt shook shelves and rattled nerves. >> it was pretty scary. i was frightened. in fact, i was shaking. >> reporter: at convenience stores not far from the epicenter in encino, a scramble to safety. >> i think this one just like rattled me because it woke me up. >> whoa! >> earthquake. >> big earthquake right now. >> reporter: the 4.4 earthquake struck during the morning rush. >> thank you, coming up more problems for a -- >> earthquake. we're having an earthquake.

>> reporter: many feared this could be the big one. >> it appears to have stopped. we're going to -- >> reporter: millions felt the shaking up to 40 miles away. there was no significant damage. at cal tech, the earthquake early warning system, a work in progress, was triggered two seconds before the temblor. >> this earthquake was the biggest that we've had in the l.a. area in five years. >> reporter: dr. lucy jones, a seismologist with the u.s. geological survey, says this is a wake-up call. >> we'd really like to use this as a time to remind people, you decided you wanted to live in l.a., that means living with earthquakes. are you ready for it? they aren't all going to be this small. >> reporter: on sunday near chile, a 6.7 quake triggered a tsunami warning. just last week in the pacific, a 6.8 rattled northern california. but experts say the quakes are not connected. >> there's no reason to think it's a precursor for a big one. the takeaway from today is, earthquakes are normal. they should be thought of as an everyday part of living in los

angeles. >> reporter: today's quake struck on a fault line that hasn't seen much activity over the last 20 years. but because it shook an area that is so populated and densely urban, in encino and westwood, folks were certainly talking about it today. it is a reminder to us all in this region, we live in earthquake country. >> all right, miguel, thank you. we're back in a moment with a big headline in the fight against cancer. and news about early detection.

shocking news here in new york today. l'wren scott, one of the top fashion designers and celebrity stylists in the country and long-time girlfriend of mick jagger, was found dead in her apartment in what authorities say is an apparent suicide. a spokesperson for jagger, who just landed in australia on tour with the rolling stones, says the singer is completely shocked and devastated. the pair had been in a relationship for well over a

decade. as she turned a successful modeling career into a successful career as a designer. her clothes, worn by everyone from first lady michelle obama to hollywood stars like nicole kidman. law enforcement officials say l'wren scott apparently hanged herself. her body was discovered by her assistant, and there was no note found and no signs of foul play. she was 49 years old. there's more evidence tonight about why early detection is key in the fight against colon cancer. in the past decade the rate of the disease among older americans has fallen by 30%, according to the american cancer society. researchers point to more people getting colonoscopies. still, just over half those who should be screened get the procedure. imagine looking out the window onboard your flight and seeing this. a panel came off the wing of a delta air lines flight on sunday. it was flying from orlando to atlanta carrying 185 passengers and crew. the mishap did not affect the

plane's ability to land, and everyone was okay. big news today from a member of our nbc news family. our friend savannah guthrie after a nearly year-long engagement got married over the weekend near her hometown of tucson. and the surprises don't end there. she and her new husband mike feldman revealed they're expecting a baby in late summer. savannah was back on the "today" show set this morning. they'll take a honeymoon later on. our congratulations to the happy couple. when we come back, making a difference. one woman's tireless effort to bridge a very important gap.

"making a difference" brought to you by pfizer. >> our "making a difference" report tonight deals with a tough subject, specifically poverty and hunger. new evidence out today shows some 20 million children in this country are on food stamps. getting their most basic needs met can be a daily struggle. but one new england woman is trying to change that and we get her story from nbc's ron mott. >> double word. >> reporter: when laurie argue and her husband hit a rough patch financially, feeding their three girls -- evelyn, abbie and celia -- became a nonstop heartache.

>> my husband would be sick over it, not being able to provide for his family. it bothered him a lot. it was an everyday concern. >> reporter: going to school was comforting, free meals there. but what about weekends? this army of volunteers for the nonprofit end 68 hours of hunger fills the void. >> you haul, i'll pack. >> reporter: bagging up enough food for two breakfasts, two lunches and three dinners, with enough left over to share, given in such a way to avoid embarrassment. >> we see a brighter child on monday morning. we see a more focused child on fridays. they're waiting for the end of the day to get their bag. >> reporter: clair bloom, a retired naval officer, founded the program three years ago in new hampshire and has since taken to it maine and most recently, california. >> this is a nearly invisible problem. kids don't come to school and say, my dad lost his job and we didn't have anything to eat this weekend. they don't come to school and say that. so we have to be really observant to clue in to the

behaviors that they demonstrate that show us, these are hungry kids. >> reporter: she spent thousands of her own money to get 68 hours off the ground. now supported by grants and donations. growing from 19 students that first year to 800 today and counting. redefining her life's purpose along the way. >> i could not imagine doing anything different. i feel, this is honest and true, i feel like this is what i was put on earth for, is to feed these kids. >> reporter: kids like the argue girls. >> it was such a relief. it really was amazing. >> reporter: no longer wondering where their next meal is coming from. ron mott, nbc news, dover, new hampshire. that's our broadcast for this monday night. thank you for being with us. i'm lester holt in for brian who will be back tomorrow. for all of us at nbc news, good night.

i'm so thankful to have additional police members down here because downtown needs it. >> some very good timing. thieves hit her san jose store today, but officers caught the suspected shoplifter in less than an hour. good evening and thanks for joining us on this monday. i'm raj mathai. >> i'm jessica aguirre. new at 6:00, extra boots on the ground met another in the squad car. those patrols are paying off. nbc marianne favro is downtown

live and marianne, you were there when officers tracked down the suspect. >> reporter: i certainly was, jessica. what i can tell you was so impressive is how fast they were able to apprehend the suspect. the next time you're in downtown san jose, you'll likely notice something new, four san jose police officers and a sergeant walking the streets. they are part of a new downtown foot patrol program that started this month. today, they focussed on fountain ally near santa collar ray and first street but the goal is to address many issues downtown. >> drug dealing, graffiti, prostitution, again, gang violence, maybe that's occurring, robberies, street-level robberies, things like that. >> reporter: the city counsel voted to allocate $200,000 from the general fund to pay the over time for these officers to walk this beat. >> we've been hearing over and over concerns about difficulty in being able to have response om